This invention relates to pumps and, in particular, to nonaerosol pump sprayers.
Noncontainer pressurizing pump sprayers commonly utilize an integral cylinder and plunger arrangement to generate pressure to expel liquid, such as insecticide and fertilizer from a container. Noncontainer pressurizing pump sprayers are desirable in that they do not utilize pressurized containers which must be handled carefully and at controlled temperatures to avoid the risk of explosion. Noncontainer pressurizing pump sprayers have a number of other advantages, including not using propellants which destroy the ozone and being relatively inexpensive.
There are two common varieties of noncontainer pressurizing pump sprayers: pump sprayers that are pressurized on the upstroke and pump sprayers that are pressurized on the downstroke. Pump sprayers that are pressurized on the downstroke typically utilize a return spring which biases the plunger upward after the pressurization stroke. These sprayers suffer from the drawback that it is often undesirable to store or ship the pump sprayer with the plunger in the up position. Accordingly, the pump sprayer is generally shipped and stored with the return spring in a compressed position, causing the spring to fatigue and begin to wear out prematurely. Likewise, in the event of the inadvertent release of the return spring, the plunger cannot be depressed without pressurizing the fluid in the container. In the case of insecticide or other toxic chemicals, this is often undesirable.
While pump sprayers that are pressurized by pulling the plunger upward have the advantage of not having the plunger being forced outward inadvertently, they too, suffer from a number of drawbacks. For example, once the plunger is drawn upward, it is generally not possible to lower the plunger without discharging fluid. As drawing the plunger upward creates a relatively large volume of pressurized liquid, this either requires that a relatively large amount of fluid be wasted or the device be stored with the plunger extending outward.
U.S. Pat. No. 4,174,055, to Capra, et al., discloses an alternative dispenser. The disclosed dispenser incorporates a plunger which pressurizes the fluid on the upstroke, but also is provided with a separate return spring and collar for purposes of lowering the plunger handle independently of the main plunger piston. While this arrangement has advantages, it is more complicated and expensive than other pump sprayer arrangements. Further, while the system provides for slow bleeding off of pressure, the sprayer remains in a pressurized state for some time. Significantly, this substantially increases the risk of inadvertent discharge of chemicals by adults or children who may come into contact with the device.
The present invention includes an apparatus and pump attachment particularly adapted to form a noncontainer pressurizing pump sprayer which overcomes the drawbacks of the prior art. The apparatus desirably includes an attachment having a pump sprayer which is pressurized on the upstroke, enabling the sprayer to be shipped and stored in a relaxed position. Importantly, however, the plunger is adapted to permit the plunger to be quickly and easily lowered and the apparatus depressurized without discharging fluid. Significantly, these advantages are provided in a apparatus which is particularly adapted to be inexpensively manufactured and includes few moving parts, to enhance reliability.
One aspect of the invention is a pump attachment for a container defining a neck including a body, a coupling, a shaft, a piston, an inlet valve and a biasing member. The body defines an elongate chamber having a first end, a second end, and an interior wall extending between the first end and the second end. The coupler is sized and shaped to secure the body to the neck of a container. The shaft extends through the opening in the first end of the chamber and defines an internal flow channel. The piston is reciprocally mounted within the chamber and defines an inner annular surface surrounding the shaft and an outer annular surface sized and shaped to form a sealing engagement with the interior wall of the body. The piston separates the chamber into an upper portion above the piston and lower portion below the piston. The inlet valve is at the second end of the body and is configured to permit the flow of fluid into the chamber and restrict the flow of fluid out of the chamber. The biasing member is positioned between the piston and the first end of the chamber.
The attachment defines a first sealing surface substantially fixed with respect to the piston and a second sealing surface substantially fixed with respect to the shaft. The first sealing surface and the second sealing surface have a first position wherein the first sealing surface and the second sealing surface cooperate to prevent the flow of liquid between the piston and the shaft. The first sealing surface and the second sealing surface have a second position wherein the first sealing surface and the second sealing surface permit the flow of liquid between the piston and the shaft.
Advantageously, the shaft includes an outwardly extending surface which prevents the piston from sliding beyond the one end of the shaft. Likewise, the attachment desirably includes a first O-ring mounted on the shaft which defines the second sealing surface and an inwardly tapered seat which defines the first sealing surface. Alternatively, the piston may comprise one piece and define an upper outer annular surface sized and shaped to form a sealing engagement with the interior wall of the body and a lower outer annular surface sized and shaped to form a sealing engagement with the interior wall of the body. Desirably, the upper outer annular surface is defined by an upper lip adapted to flex outward in response to downward pressure and the lower outer annular surface is defined by a lower lip adapted to flex outward in response to upward pressure.
The attachment may also include a spray nozzle communicating with the internal flow channel and an actuator for selectively preventing the flow of a fluid through the spray nozzle.
The attachment desirably includes a handle secured to the shaft and a latch movable between a first location wherein the latch generally prevents the shaft from being drawn through the first end of the body and the second location wherein the latch generally permits the shaft to be drawn through the first end of the body. Alternatively, the handle is integrally formed with the shaft so as to form a single piece plunger, thereby eliminating a potential leak point.
Another aspect of the invention is an apparatus including a container defining a neck and an attachment. The attachment includes a body, a coupler, a shaft, a piston, an inlet valve, and a biasing member. The body defines an elongate chamber having a first end, a second end and an interior wall extending between the first end and the second end. The coupler is sized and shaped to secure the body to the neck of the container. The shaft extends through an opening in the first end of the chamber and defines an internal flow channel. The piston is reciprocally mounted within the chamber and defines an inner annular surface surrounding the shaft and an outer annular surface sized and shaped to form a sealing engagement with the interior wall of the body. The piston separates the chamber into an upper portion above the piston and a lower portion below the piston. The inlet valve at the second end of the body is configured to permit the flow of fluid into the chamber and restrict the flow of fluid out of the chamber. The biasing member is positioned between the piston and the first end of the chamber.
The attachment includes a first sealing surface substantially fixed with respect to the piston and a second sealing surface substantially fixed with respect to the shaft. The first sealing surface and the second sealing surface have a first position wherein the first sealing surface and the second sealing surface cooperate to prevent the flow of liquid between the piston and the shaft. The first sealing surface and the second sealing surface have a second position wherein the first sealing surface and the second sealing surface permit the flow of liquid between the piston and the shaft.
Another aspect of the invention is a method of arming and disarming a spray apparatus, including a container containing fluid and an attachment mounted thereto having a body defining an elongate chamber, a shaft extending through an opening in the chamber, the shaft defining an internal flow channel, a piston reciprocating mounted in the chamber, a check valve and a biasing member, including (1) moving the shaft in a first direction relative to the body, thereby moving the piston in the direction and drawing fluid from the container into the chamber through the check valve and compressing the biasing member; (2) permitting the biasing member to force the piston against the fluid in the chamber in a second direction pressurizing the fluid; (3) releasing liquid from the chamber through the internal flow channel in the shaft; and (4) moving the shaft in a second direction-relative to the body and the piston to release a seal between the piston and the shaft, thereby permitting the flow of fluid between the piston and the shaft depressurizing the fluid.
Another aspect of the invention is a spray nozzle including a grip, a nose having a spray end, a valve housing, a valve and an actuator. The actuator is connected to the valve. The valve housing is mounted within either the grip or the nose. The valve housing defines a closed end, an inlet port and an outlet port. The valve is mounted within the housing and has a flow portion, a first seal on one side of the flow portion and the second seal on the other side of the flow portion. The valve has a first position wherein the valve prevents the flow of fluid between the inlet port and the outlet port, and a second position wherein the valve permits the flow of fluid between the inlet port and the outlet port. The first seal and the second seal are positioned to one side of the inlet port when the valve is in the first position. The first seal and the second seal are positioned on opposite sides of the inlet port and the outlet port when the valve is in the second position. Desirably, the valve comprises a one-piece shaft member and no more than two O-rings.
Yet another aspect of the invention is an assembly for a container. The assembly includes a grip, a coupler sized and shaped to secure the grip to the neck of a container, a plug and an adaptor. The grip includes a handle portion and a stem portion. The handle portion has a first inner wall defining a first flow channel having a first outlet. The stem portion defines a second inner wall defining a second flow channel having a second outlet. The first flow channel and the second flow channel intersect at the outlet of the second flow channel. The plug is mounted within the first flow channel and has a first position wherein the plug prevents fluid flow from the second outlet to the first outlet, and a second position wherein the plug permits fluid flow from the second outlet to the first outlet. The adaptor has an inner section sized and shaped to be inserted into the first flow channel to move the plug between the first position and the second position. Desirably, the plug further includes an inner flow channel through which fluid is flowable when the plug is in the second position. The adaptor preferably comprises a connector for securing a piece of tubing to the handle portion of the grip.
Finally, yet another aspect of the invention is an assembly including a container and a sprayer. The container defines a wall, a first stud and a second stud. Each of the first stud and the second stud include a head portion and a stem portion. The sprayer has a spray end and a wall. The wall defines a first opening and a second opening. Each of the openings includes a first portion wider than the stem portion and narrower than the head portion, and a second portion wider than the head portion so that the head portion of the stud is insertable therethrough. Advantageously, the container includes a seam and the first stud and the second stud intersect the seam. Preferably, the second portion of the opening is positioned closer to the spray end than the first portion of the opening. Desirably, for each of the first stud and second stud, the head portion overhangs the stem portion a first overhang distance on a first side, and a second overhang distance on a second side. At least one of the first overhang distance and the second overhang distance is advantageously at least 0.015 of an inch.